1. Field of the Invention
The present invention relates to a plastic injection-molded gear used in power transmission devices, such as various automobile components, industrial machinery, and precision machinery.
2. Description of the Related Art
Since the past, plastic injection-molded gears have been widely used in power transmission devices, such as various components of automobiles and industrial machineries. The plastic injection-molded gear is lighter and has quieter work noise than a metal gear.
Among plastic injection-molded gears such as those described above, FIG. 12 and FIG. 13 show a plastic injection-molded gear 200 forming a reduction gear. In the plastic injection-molded gear 200 shown in the diagrams, a rim 202 is formed in a cantilevered manner on an outer peripheral edge of a web 203. Teeth 201 are formed on an outer periphery of the rim 202. A rubber 205 is housed within a ring-shaped recess (space) 204 formed between an inner peripheral side of the rim 202 and a side surface of the web 203. A pressing component 206 is disposed on a side surface of the rubber 205. Impact that takes effect when rotation is started and when rotation is stopped is absorbed by a damper means 207, including the rubber 205 and the pressing component 206 (refer to Patent Literature 1 and Patent Literature 2).
Patent Literature 1: Microfilm of Utility Model Application No. Heisei 2-91585 (Utility Model Laid-open Publication No. Heisei 4-51056) (see FIG. 1 and FIG. 2, in particular)
Patent Literature 2: Utility Model Laid-open Publication No. Heisei 6-78650 (see FIG. 1, in particular)